'A lot of people want
to know who the father is," says actress Laura Allen

from "The 4400," USA Network's runaway summer hit.

Can't blame them.

Not since Agent Scully and "The X-Files" has a character shown up in prime time pregnant with a potentially alien life form.

"There's been a lot of response on the USA Network website about the alien baby," says the program's surprised co- creator, Scott Peters. "A lot more chatter than we thought."

In the series, whose final episode airs Sunday night, Allen, 30, plays Lily Moore, one of a group of returned abductees who haven't aged and who have no memories of captivity.

Lily meets up with Korean War soldier-returnee Richard Tyler (Mahershalalhashbaz Ali), who back then had a relationship with Lily's grandmother.

Comparisons to "The X-Files" and even "Rosemary's Baby" come quickly. But Allen says this romantic tidbit has viewers guessing that the mysterious fetus may somehow be the love child of Lily's grandmother and the pre-abduction Tyler.

The paternity mystery has other possible explanations. Was Lily impregnated by an abductee other than Richard while they were in the twilight zone? Is it a self-generated spiritual being?

But most fans are probably hoping that Richard's the father because of the exceptional chemistry between them.

"It's like partner dancing," says Allen about those rare occassions where two actors "fall into sync with each other."

Allen and Ali don't try to analyze the magic happening on screen. "We don't talk about it because we don't want to ruin it," she says.

Raised on Bainbridge Island in Washington State, Allen performed in local musical theater as a child. "I had hopes of going to New York to be a chorus girl," she jokes.

Allen did come East — to get a B.A. from Wellesley.

Considering a career in law, she worked for the NYPD in the Victims Services bureau. But soon the lure of performing again got the better of her.

With a stint on the soap "All My Children," a role in "Mona Lisa Smile" and a just-wrapped indie film under her belt, Allen is now dodging questions about the fate of Lily and Richard.

"Keep your eye on Jordan," says Allen, referring to abductee Jordan Collier (Billy Campbell), a wealthy mogul who encourages the returnees to band together to protect themselves from exploitation — and who also happens to be Richard's new employer.

Allen is also happily aware of the rumors that "The 4400" might get a green light for more episodes. "I think this could take on a cult following," she says.